Wyniki wyszukiwania - BazTech

1

Evaluation of single lane parallel-type entrance ramp terminal using vehicle dynamics model for freeways

Saremi Niousha, Kordani Ali Abdi, Zarei Mohammad, Kohansal Akram

Architecture Civil Engineering Environment

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2023

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Vol. 16, no. 1

85--100

EN

Providing an appropriate length of highway entrance ramps is an important feature that should be considered in freeway design. The recommended minimum acceleration lane length in the Green Book of the American Association of State Highway and Transportation Officials (AASHTO) is currently used for designing entrance ramp terminals. However, in some cases, traffic congestion and crashes are observed when heavy trucks enter freeways, which indicates they could not accelerate enough and did not reach the merge speed at the end of the acceleration lane. Therefore, several scenarios were simulated using a dynamic simulation model (TruckSim) for heavy vehicles with weight to power ratios of 61, 67, 86, and 108 (kg/kW) and grades of zero, ±3, and ±5%. Subsequently, a linear regression model was presented to calculate acceleration lane lengths. The results showed that the acceleration rate of heavy vehicles is not adequate, especially in upgrades. For example, at +5% upgrades, heavy trucks cannot accelerate to the merge speed mentioned in the AASHTO. Conversely, the acceleration rate of heavy vehicles increased in downgrades; therefore, some heavy vehicles were able to achieve merge speed along the proposed length of AASHTO.

2

Urban traffic noise of heavy vehicles in octave bands

Bąkowski Andrzej, Dekýš Vladimir, Radziszewski Leszek, Świetlik Paweł

Vibrations in Physical Systems

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2020

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Vol. 31, nr 1

art. no. 2020103

EN

In this paper same results of heavy vehicles traffic measurements were used to simulate the noise measurands by the CNOSSOS-EU method for this purpose. The heavy vehicles traffic volume and velocity were recorded by permanent automatic monitoring station. The noise was calculated in octave bands according to the CNOSSOS-EU method. The positional and not positional measures of traffic noise were proposed for data scattering. The results was described using parameters such as the median, average peak noise, average maximum noise, average background level, first and third quartiles and relative measures of noise. Analyzes carried out for the tested section of the road showed that the traffic of heavy vehicles is not always the main source of road noise. It has been shown that maximum values of the acoustic pressure occur for the frequency of f0 = 500 Hz. The dispersion of noise and type A uncertainty of the results were evaluated.

3

Design of the vibrostabilisation stand for reducing residual stresses in discs used in the construction of multi-plate clutches and brakes

Jaroszewicz Jerzy, Łukaszewicz Krzysztof, Antonyuk Vladimir

Acta Mechanica et Automatica

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2019

|

Vol. 13, no. 1

37--44

EN

Heavy-duty, oil-cooled brake discs (MMOTs) are often used in heavy-duty brake systems manufactured by companies such as Caterpilar, Clark, Komatsu and Liebherr. These discs are usually made of special steels, and in most cases, the flatness of the working surfaces should not exceed 0.15–0.30 mm. Although the technological processes of friction disc production include several stages of heat treatment and grinding, the required accuracy is not achieved in some cases. In addition, the remaining residual stresses lead to the deformation of the discs during their lifetime. In production practice, three methods are used to reduce residual stresses: thermo-fixing, dynamic stabilisation and vibratory stabilisation consisting in bringing discs to transverse resonance vibrations and maintaining resonance until significant stress reduction. The article proposes a method of stabilising the discs using the resonance phenomenon at the first few frequencies. In this article, Cauchy’s function method and characteristic series method are used to develop solution value problem for clamped circular plates with discrete inclusions as concentrated masses and springs. Calculation methods for quick estimation of the own frequency of discs with additional ring mass enabling the use of low power vibration inductors are presented. The use of a special membrane and a pneumatic cushion in the construction of the stand allows to induce vibrations of higher frequencies.

4

Tracking control and robustness study of shifting process

Zhao X., Guan Ch.

Archives of Transport

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2018

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Vol. 46, iss. 2

97--104

EN

Heavy dump vehicles are usually working with big load changes and bad work environment, thus change the friction performance of transmission clutches, as well as great affect the shift quality seriously, which influence the vehicle performance. Many researchers developed a lot to design a useful automatic transmission control system. Using PID tracking control and Monte Carlo method, the controller based on an dynamic model was set up to analyze the shifting process of automatic transmission and its robustness in this paper. The shift process was divided into four stages, low-gear phase, torque phase, inertia phase and high-gear phase. The model presents the process from the first gear to the second gear when the torque has big change. Since the jerk and the friction work of clutch are both related to the speed of clutch which was easier to control, it was chose as the target to control the oil pressure for satisfying the requirement of shift quality. The simulation software, Maplesim and Simulink, were used to build the vehicle model and shifting controller for simulation under different working conditions, and the maximum jerk was changed from 34 m/s3 to 12 m/s3 after the optimization. In this paper the Monte Carlo has been used to quantize and evaluate the robustness of the closed-loop system for the friction coefficients and output torque of turbine variation leading by the friction feature parameters and throttle angle changed. Monte Carlo method was used to analyze the effectiveness and robustness of PID controller, which proves that it has good control effect when the throttle is ongoing minor fluctuations. When the throttle is full opening, a quadratic optimal controller based on disturbance is designed by the method of multi-objective optimization. When it changes within 20 percent, PID controller was designed under the guidance of tracking thoughts. The results also show that the controller could still obtain better effect when the friction coefficient ranged from -40 % to 40 % as well as engine torque changed from -20 % to 20 %, which indicates the robustness of controller.

5

Influence of traffic flow variability of heavy vehicles and temperature on pavement fatigue life

Spławińska M., Zieliński P., Burnos P.

Roads and Bridges - Drogi i Mosty

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2015

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Vol. 14, no. 2

117--132

PL

W pracy przedstawiono wpływ zmienności temperatury i natężeń ruchu pojazdów ciężkich na trwałość zmęczeniową podatnych nawierzchni drogowych (nawierzchnie z podbudową z kruszywa niezwiązanego oraz z betonu asfaltowego. Podziału terytorium Polski na grupy jednorodne ruchowo i temperaturowo dokonano przy łącznym wykorzystaniu metod ilościowych (analiza skupień oraz jakościowych (przynależność geograficzno-funkcjonalna. Podstawą podziału był kształt profili zmienności temperatury oraz natężeń ruchu w kolejnych miesiącach w roku i w następujących po sobie sezonach. Po określeniu jednorodnych grup wyznaczono dla nich reprezentatywne profile zmienności natężeń ruchu oraz temperatury, które wykorzystano do obliczenia trwałości zmęczeniowej konstrukcji nawierzchni. Trwałość zmęczeniową wyznaczono wykorzystując kryterium zmęczeniowe warstw asfaltowych według Instytutu Asfaltowego. Obliczenia stanu naprężeń i odkształceń w nawierzchni przeprowadzono z wykorzystaniem programu BISAR. Uzyskane wyniki pozwoliły na porównanie oraz wskazanie różnic w otrzymanych trwałościach nawierzchni w zależności od przyjętych wartości temperatury ekwiwalentnej.

EN

The paper presents the effect of temperature variability and traffic flow variability on fatigue life of flexible road pavements (pavements with the subgrade made of unbound aggregates and asphalt concrete'. The division of the territory of Poland for the homogeneous groups in terms of movement and temperature was made at the use of quantitative methods (cluster analysis' and qualitative methods (geographical and functional affiliation'. The basis for the division was the shape of the profiles of temperature and traffic flow variability in subsequent months of the year and in successive seasons. After determining homogeneous groups, representative profiles of traffic flows and temperature variability were established, which were used to calculate the fatigue life of pavement structure. Fatigue life was determined using the criterion of fatigue of asphalt layers according to the Asphalt Institute. The calculations of stress and strain in the pavement were carried out using the program BISAR. The results have permitted comparison and identification of differences in pavement durability obtained depending on the values of equivalent temperatures.

6

Wpływ natężenia ruchu pojazdów ciężkich na trwałość konstrukcji nawierzchni drogowej

Spławińska M., Zieliński P.

Drogownictwo

|

2015

|

nr 3

98--104

PL

Przedstawiono wpływ sezonowej zmienności natężeń ruchu pojazdów ciężkich oraz różnych wartości temperatury ekwiwalentnej obowiązujących w Polsce, na trwałość zmęczeniową nawierzchni drogowej. Analizie poddano trzy rodzaje konstrukcji asfaltowych nawierzchni podatnych w odniesieniu do KR 4 (nawierzchnie z podbudową z kruszywa niezwiązanego, z betonu asfaltowego oraz z mieszanek MCE wykonanych w recyklingu na zimno). Określono również typowe profile sezonowej zmienności natężeń ruchu pojazdów ciężkich, które umożliwiają rozłożenie ruchu na poszczególne miesiące roku.

EN

Paper presents the influence of seasonal traffic flow variability of heavy vehicles and different values of equivalent temperature on fatigue life of pavement. Three types of flexible asphalt pavement construction with different base type (unbound aggregate mixture, asphalt concrete mixtures and cold recycled base) were analyzed. Typical profiles of seasonal traffic flow variability of heavy vehicles that allow the distribution of traffic on subsequent months were also defined.

7

Analiza obciążenia osi pojazdów ciężkich na podstawie danych z ważenia pojazdów w ruchu (WIM)

Ryś D., Judycki J., Jaskuła P.

Drogownictwo

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2015

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nr 10

328--335

PL

W artykule przedstawiono rozkłady obciążenia poszczególnych rodzajów osi pojazdów. Podstawą analizy były dane z ważenia 12 mln pojazdów ciężkich w okresie od roku do 3 lat na 10 stacjach ważenia pojazdów w ruchu, z ang. weigh in motion (WIM), w Polsce. Celem artykułu, oprócz przedstawienia rozkładów, jest ocena wpływu dopuszczalnego obciążenia osi na rzeczywiste obciążenia osi pojazdów ciężkich. Przedstawiono opis matematyczny funkcji rozkładu obciążenia osi jako rozkładu złożonego z dwóch rozkładów normalnych. Opisano procedurę i wyniki obliczeń parametrów funkcji rozkładów. Określono rozkłady średnie z rozróżnieniem dopuszczalnego obciążenia osi 115 kN i 100 kN. Stwierdzono, że rzeczywiste obciążenia osi są wyższe na drogach na których dopuszczalne obciążenie osi wynosi 115 kN.

EN

The paper presents load distributions of particular vehicle axle types. The analysis based on the data from weighing in motion of 12 million heavy vehicles in the period from one to three years on 10 stations in Poland. The objective of the paper, besides the determination of axle load distributions, is to reveal how the legal axle load limit impacts on the real axles loads distributions. The function of axle load distribution is assumed as the function composed of two normal distributions. The procedure and results of calculations of distribution parameters are presented in the paper. The average axle load distributions for road with legal axle load limit 115 kN and 100 kN are determined separately. It was concluded that the real axle loads are higher on roads with legal axle load limit 115 kN.

8

Innowacyjność w rozwoju infrastruktury drogowej w Polsce

Rafalski L.

Nowoczesne Budownictwo Inżynieryjne

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2013

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Nr 1

32-38

PL

W rozwoju transportu drogowego i infrastruktury drogowej wprowadzane są innowacje produktowe, procesowe, marketingowe i organizacyjne. Międzynarodowe i krajowe prognozy rozwoju transportu są optymistyczne, co powinno sprzyjać wprowadzaniu innowacji w infrastrukturze drogowej.

EN

In the development of road transportation and road infrastructure innovations in manufacture, process, marketing and organization can be implemented. International and national prognoses of transportation development are optimistic, and they should promote implementation of innovations in road infrastructure. The producers of heavy vehicles and their users aim to increase total vehicle weights and axle loads. International organizations: the Joint Transport Research Committee (JTRC) and the Forum of National Highway Research Laboratories (FEHRL) study the influence of increased loads on road infrastructure as well as they define directions of the innovative solutions of trucks and road infrastructure. In Poland the programme of development of national and district roads creates an opportunity to implement innovative solutions. In spite of obstacles in the development of innovations, new solutions are investigated and implemented in road infrastructure.

9

Dotychczasowe i przyszłe możliwości prognozowania ruchu na drogach krajowych Lubelszczyzny

Kukiełka J., Kukiełka J., Ziemiński P.

Drogownictwo

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2012

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nr 11

377-381

PL

Metoda modelowa daje obecnie największe możliwości prognozowania ruchu pojazdów. W tej metodzie niezbędna jest wiedza o liczebności podróży miedzy poszczególnymi źródłami i celami ruchu, rodzaju pojazdów oraz rozkładu ruchu na sieć. Takie informacje uzyskuje się z wywiadów na drogach oraz ze stacji ciągłych pomiarów ruchu i ważenia pojazdów w ruchu. W artykule przedstawiono analizę obciążeń nawierzchni drogowych ruchem oraz propozycje jego prognozy, głównie w aspekcie projektowania przebudowy dróg lub wzmacniania nawierzchni.

EN

Model method of traffic forecasting gives presently biggest capability. In this method, knowledge on trip numbers between origins and destinations, types of vehicles and traffic assignment is necessary. These data come from interviews and from permanent traffic measurement stations, and from weighing in motion. In the paper, present analysis of traffic load on road pavement and proposals of load forecast, in aspect of design of road reconstruction and pavement strengthening, is presented

10

Vehicles in motion parameters measurement pre-selection system

Mitas A. W., Konior W.

Archives of Transport

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2012

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Vol. 24, iss. 1

43-61

EN

Heavy goods vehicles moving on public roads are driven by people belonging to all walks of society, including those, who for the price paid by others are ready to multiply their own profits. This problem is discussed in the article, in particular in terms of overloading car's. There is pointed out on the technical implications of such actions. Later in the paper are presented the basic assumptions of lorries pre-selection weighting, which could be treated as a potential reason to the implementation of time-consuming exact weighting procedure. The discussion of hardware-software solution of pre-selection weighing systems was related to practical applications in national conditions. The article highlighted the problem of dynamic effects, significantly influencing the process of weighting in motion.

PL

Pojazdy ciężarowe poruszające się po drogach publicznych kierowane są przez ludzi należących do pełnego przekroju społecznego, w tym także takich, którzy za cenę płaconą przez innych są gotowi do pomnażania własnych zysków. Problem ten poruszono w artykule, w szczególności w aspekcie przeciążenia samochodu. Wskazano na skutki techniczne takiego działania. W dalszej części opracowania przedstawiono podstawowe założenia preselekcyjnego ważenia samochodów ciężarowych, stanowiącego przyczynek do wykonania czasochłonnej procedury ważenia dokładnego. Dyskusję rozwiązania sprzętowo-programowego systemów ważenia preselekcyjnego odniesiono do praktycznych aplikacji w warunkach krajowych. W artykule zwrócono uwagę na problematykę dynamicznych efektów, istotnie wpływających na proces ważenia w czasie ruchu pojazdu.

11

Example of experimental validation and calibration of a finite element model of a heavy vehicle

Szurgott P., Kwaśniewski L., Wekezer J. W.

Journal of KONES

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2010

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Vol. 17, No. 1

433-440

EN

An example of the experimental validation ofafinite element model of a selected heavy vehicle is presented in the paper. A truck tractor with a three axle single drop lowboy trailer and the total weight of 20 tons was selected as a representative for the tests. The major goal of the conducted studies was to develop a well validated the numerical model of a heavy vehicle applicable for computer simulation of dynamic interaction between a vehicle and a bridge or road structure. Therefore, only several components of the vehicle, affecting the vehicle-road interaction, like wheels and the suspension systems, were modelled in detail. The rest of components were simplified and considered as rigid bodies. The finite element model included fully pneumatic tires and the suspension system modelled with discrete massless springs and dampers. Numerical analyzes were performed using the LS-DYNA computer code. The validation and calibration procedure proposed in the current paper was carried out in two steps. In the first one, some parameters such as material densities, thickness of selected elements, were modified to achieve the correct mass distribution in the model based on the measured axle loads. In the next step the stiffness and damping parameters of the suspension system were evaluated based on the results of the experimental tests. The spring and damping coefflcients at all axles were adjusted until the performance of the FE model closely matched that of the actual vehicle.

12

Wpływ pojazdów ciężkich na nawierzchnie drogowe - analiza współczynnika agresywności

Malicki K.

Drogownictwo

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2007

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nr 5

160-166

PL

Pojazdy ciężkie powodują stopniowe niszczenie nawierzchni drogowej. Są różne podejścia do przeliczania pojazdów rzeczywistych na standardowe: praktyczne oparte na współczynnikach i analityczne poprzez określanie trwałości zmęczeniowej. Autor wykonał analizę porównawczą kilkoma metodami, przedstawił wyniki obliczeń i sformułował wnioski.

EN

Heavy vehicles cause gradual deterioration of road pavement. There are various approaches to conversion of real vehicles into standard vehicles, practical based on coefficients and analytical based on fatigue durability. The author made comparative analysis of several methods, presented results and formulated conclusions.